The present invention relates to safety locks for house doors and the like and particularly to safety locks adapted to be operated by keys having a front active profile, of the type comprising:
an outer drum member which is to be fixed to the lock casing, having a substantially cylindrical inner cavity, PA1 a cylindrical body which is coaxially and rotatably supported within the inner cavity of the drum member, said cylindrical body having an inner cavity opening on its rear face, PA1 a disk covering the inner cavity of the cylindrical body and connected to the rear face of the latter, said disk having an aperture in correspondence with the axis of the cylindrical body, PA1 a T-shaped element having a stem slidably mounted within the axial aperture of said covering disk along the axis of the cylindrical body and a portion including the T-brackets housed within the cavity of said cylindrical body, said brackets having ends slidably mounted within longitudinal grooves formed in the surface of the inner cavity of the cylindrical body, PA1 a tab-like locking member slidably mounted within a slot formed radially through the wall of the cylindrical body, the radially outer end of said tab member being adapted to engage a cooperating cavity formed on the inner wall of the drum member to prevent a rotation of the cylindrical body with respect to the drum member, PA1 a plurality of safety plates arranged parallel to each other side by side, said plates having notches and being housed within said cavity of the cylindrical body so as to move freely in their planes with respect to each other, said notches defining a seat for receiving the inner end of said tab member when said plates reach a predetermined position with respect to each other, and PA1 cam means, within the inner cavity of said cylindrical body, in contact with said tab member and adapted to hold the tab member in a position in which it engages said cavity in the drum member.
Locks of this type have been known and marketed in Italy by the Applicant for a long time and have the inconvenience of a relatively big axial bulk, due at least in part to the need of providing sufficient space for the movement of the safety plates, which are slidably mounted within the cylindrical body.